Method and apparatus for smog control



July 5, 1966 J. M. RITCHIE 3,259,1 1 7 METHOD AND APPARATUS FOR SMOGCONTROL Filed July 8, 1964 INVENTOR. JEss M. PITCH/E ATTORNEYS UnitedStates Patent 3,259,117 METHOD AND APPARATUS FOR SMOG CONTROL Jess M.Ritchie, Oakland, Calif., assiguor to Fog-Aire,

{ Inc., Oakland, Calif., a corporation of California Filed July 8, 1964,Ser. No. 381,129 3 Claims. (Cl. 123-119) This invention relatesgenerally to the reduction of air pollution, and is more particularlydirected to a method of, and apparatus for reducing the concentration ofunburned hydrocarbons in automobile exhaust gases.

The control of air pollution has become one of the major problemsconfronting large metropolitan areas. For the purpose of brevity in thefollowing description, the term smog will be used hereinafter to denotethe mixture of air pollutants generally present in the air of largeurban communities. It is known that automobile exhaust gases constituteone of the major components of smog. In particular, the unburnedhydrocarbons present in automobile exhaust gases are a major factorcontributing to the respiratory irritation which is endemic insmog-filled areas. Unburned hydrocarbons in the exhaust are produced byincomplete combustion of the fuel mixture in the combustion chambers.This incomplete combustion, in turn, is caused by carbon deposits withinthe combustion chambers. During the operation of the engine, thesecarbon deposits are heated to incandescence, thereby causingpre-ignition of the fuel mixture. Therefore, the combustion of the fuelmixture does not proceed to completion, leading to the production ofunburned hydrocarbons in the exhaust gas.

Various devices have been developed to reduce the concentration ofunburned hydrocarbons existing in automobile exhaust gases due to theforegoing circumstances. One of the most common of these devices is thecrankcase ventilator or so-called blow-by device. However, theconventional blow-by device possesses a relatively low scavengingefliciency, i.e., the reduction in the concentration of unburnedhydrocarbons in the exhaust gas attainable with such a device is quitesmall. This is due to a conventional blow-by device being arranged tomerely provide a re-cycling conduit which returns gases from theinterior of the crankcase back into the combustion chambers of theengine. Thus, the operation of a conventional blow-by device has noefiect upon the actual source of unburned hydrocarbons, namely theformation of carbon deposits in the combustion chambers, and thereforethe resulting reduction of the concentration of hydrocarbons in theexhaust gas is of relatively low order.

The present invention provides an improved method and apparatus forreducing the concentration of unburned hydrocarbons in automobileexhaust gases. Briefly, the method of the invention comprises passingcrankcase gases through a water-filled scrubber, and injecting theeflluent gas from the scrubber back into the combustion chambers of theengine. The crankcase gas becomes saturated with water vapor when itpasses through the water in the scrubber. When the saturated efiiuentvapor comes into contact with the incandescent carbon deposits in thecombustion chambers, the water vapor combines with the hot carbon in theso-called water gas reaction. The prod ucts of the water gas reaction,chiefly carbon dioxide and carbon monoxide, are expelled from thecombustion chambers into the exhaust manifold. In this manner, the meth-0d of the present invention simultaneously ventilates the crankcase andremoves carbon deposits from the engine combustion chambers. fuelmixture proceeds to completion, with a resulting marked decrease in theconcentration of unburned hydrocarbons in the exhaust gases.

Accordingly, it is an object of the present invention to provide amethod and apparatus for decreasing the con- Consequently, combustion ofthe Patented July 5, 1966 centration of unburned hydrocarbons inautomobile exhaust gases.

Another object of this invention is to provide a method and apparatusfor simultaneously ventilating the engine crankcase and introducingwater vapor into the engine combustion chambers.

Yet another object of the invention is the removal of corrosive vapor,such as sulfuric acid, and particulate matter, such as ash, rust, leadsulfate, and the like, from the crankcase of an engine to therebyminimize the contamination of crankcase oil and reduce engine wear.

Still another object of this invention is to provide for improved fueleconomy in the operation of an internal combustion engine.

A further object of the invention is the provision of a method andapparatus for simultaneously ventilating the crankcase of an internalcombustion engine and simultaneously humidifying the air-fuel intakemixture introduced thereto wherein the humidification function isentirely selfregulating in accordance with the humidity of theatmosphere.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of the preferred form of the invention which is illustratedin the drawing accompanying and forming part of the specification. It isto be understood, however, that variations in the showing made by thesaid drawing and description may be adopted within the scope of theinvention as set forth in the claims.

FIGURE 1 is a schematic representation of the scrubber apparatus of theinvention suitably connected to an automobile engine, and

FIGURE 2 is a detailed perspective view of the scrubber apparatus shownin FIGURE 1.

The method of the present invention, as noted previously, in basicrespects comprises simultaneously ventilating the crankcase of aninternal combustion engine by withdrawing blow-by gases therefrom, whilehumidifying the intake manifold of the engine. More explicitly, ventilation of the crankcase and withdrawal of gases therefrom are preferablymotivated by the intake vacuum of the engine. In this regard, arecycling flow path may he established between the crankcase and intakemanifold of the engine whereby the pressure differential existingtherebetween is in a direction to cause gas flow from the crank casetowards the manifold. Saturation of the crankcase gases is bestaccomplished by first heating the gases to lower the relative humiditythereof and thereafter saturating the heated gases with water vapor bybubbling same through water en route to the intake manifold. Preferablyheating of the gases is effected by passing the gases into heat exchangerelation to the exhaust manifold of the engine, and in this regard therecycling flow path:

may extend in close proximity to the exhaust manifold.

Saturation of the relatively dry heated gases with water vapor may thenbe facilitated by providing a column of water in the flow path at alocation between the exhaust manifold and intake manifold. For example,a scrubber bottle partially filled with water may be communicated at itslower end with the flow path at a point down-stream from the exhaustmanifold, and at its upper end with the remainder of the flow'pathextending to the intake manithe saturated gases combines with the hotcarbon to proi duce carbon dioxide, carbon monoxide, and the like, whichare expelled into the exhaust manifold. The carbon deposits are thusremoved and pre-ignition of the intake fuel mixture is substantiallyeliminated. The fuel mixture is then able to burn to completion and theconcentration of unburned hydrocarbons in the exhaust gases ismanifestly reduced.

Considering now preferred apparatus for conducting the method describedhereinbefore and referring to FIG- URE 1, there is shown a scrubberbottle 11 which is partially filled with Water 12 and is sealed by meansof a cap 13. An intake conduit 14 extends downwardly into bottle 11through cap 13, and terminates below the level of the water in aperforated loop 16. The other end of conduit 14 is wound around theengine exhaust manifold 17, and communicates with the interior of theengine crankcase by means of an opening in the valve cover 18. An exitconduit 19 communicates at one of its ends with the interior of bottle11, and at its other end with the engine intake manifold 21. Thecrankcase breather tube 22 is sealed.

Referring now to FIGURE 2, there is shown a detailed view of scrubberbottle 11 and means for mounting it within the engine compartment. Cap13 is integrally formed with a mounting bracket 23 which is attached tothe engine firewall 24 by means of screws 26. A normally-closed checkvalve 27 is disposed in cover 13, and is positioned so as to open whenthe pressure inside bottle 11 exceeds the atmospheric pressure withinthe engine compartment.

In the operation of the apparatus shown in FIGURES 1 and 2, the downwardmovement of the engine pistons creates a vacuum within intake manifold21. This vacuum is communicated to the interior of scrubber bottle 11 bymeans of conduit 19. Consequently, the interior of the engine crankcaseis at a positive pressure relative to the interior of scrubber bottle11. Blow-by gas inside the crankcase is thus forced out through opening18 in the valve cover and enters conduit 14. In its passage throughconduit 14, the blow-by gas is heated in that section of the conduitwhich is wound around the hot exhaust manifold 17. The relative humidityof the heated blow-by gas is thereby lowered below the relative humidityof the cooler blow-by gas still within the engine .crankcase. The heatedgas flows through conduit 14 and, upon exiting the conduit through theperforations in loop 16, bubbles up through the water within thescrubber bottle. By the time the blow by gas bubbles through the entirewater column, the gas is saturated with water vapor, i.e., its relativehumidity is increased to 100%. The saturated blow-by gas leaves thescrubber bottle via conduit 19, and is returned to the engine combustionchambers through intake manifold 21.

Referring now to FIGURE 2, it can be seen that check valve 27 isnormally held in the closed position by the action of gravity on thevalve stem. However, if the pressure within bottle 11 becomes greaterthan the atmospheric pressure within the engine compartment (due toleaky intake valves or a blown head gasket), the stem of valve 27 isforced upwards, thereby opening the valve and venting the excesspressure to the atmosphere. This automatic venting action of valve 27 isa safety feature incorporated into the apparatus to prevent water inbottle 11 from being forced back through conduit 14 into the crankcase.

It will be apparent from the foregoing description that the apparatus ofthe invention is a closed-loop re-cyclin-g device which simultaneouslyventilates the crankcase and humidifies the fuel-air intake mixture,thereby significantly reducing the concentration of unburnedhydrocarbons in the engine exhaust gases. It should be noted, however,that several other advantages attach to the novelventilation-humidification mode of operation of the apparatus. First,the corrosive acid vapor in the blow-by gas (chiefly sulfuric acidresulting from the combustion of sulfur in the gasoline) is removed fromthe re-cycle stream by the scrubbing action of the water in bottle 11.The removal of the acid vapors eliminates a major cause of engine wear,i.e., the condensation of acid vapor in the crankcase oil, therebylowering the pH of the oil to a point where the oil has a corrosiveaction on metal engine parts. A further feature of the apparatus is thatthe water filled scrub ber bottle functions as an effective fine-meshfilter which removes particulate matter from the recycle stream.Crankcase vapors normally carry a considerable quantity of fineparticulate matter in suspension. These fine particles, e.g., ash, ironoxide, lead sulfate, sulfur, ordinarily settle out on the surface of thecrankcase oil, thereby leading to rapid clogging of the oil filter andeventual faulty lubrication of the engine. However, the simultaneousventilation and scrubbing action of the present apparatus traps thesuspended particles in the water in the scrubber bottle, therebyeffectively removing them from the re-cycle stream.

Another feature of the apparatus is that the fine oil mist (theso-called oil ends) in the crankcase interior is insoluble in the waterwithin the scrubber bottle. Consequently, this mist of oil passesthrough the scrubber bot tle, and is returned to the intake manifold,thereby resulting in continuous beneficial lubrication of the valves,cylinder heads, and tops of cylinders.

A further feature of the apparatus is that the gasoline which is lostinto the crankcase on the compression stroke is insoluble in the waterwithin the scrubber bottle. Hence, this gasoline, which would ordinarilybe vented out the crankcase breather tube, is returned to the intakemanifold and burned by the engine. Fuel economy is thus improved.

An important aspect of the operation of the apparatus is that thehumidification function is entirely self-regulating. On days when theatmospheric humidity is high (resulting in a high partial pressure ofwater vapor within the crankcase), an equilibrium is reached between thehumidity of the crankcase vapor and the humidity of the efiiuent gasfrom the scrubber bottle. Consequently, very little water is evaporatedinto the re-cycle stream from the scrubber bottle. Conversely, on daywhen the atmospheric humidity is relatively low (resulting in a lowpartial pressure of water vapor within the crankcase), water isevaporated from the scrubber bottle into the efiiuent gas at arelatively rapid rate. It has been found that one to two ounces of waterare evaporated per galion of gasoline burned when the apparatus isoperated on dry days, i.e., atmospheric relative humidity of 30 to 50%.It will be apparent from the foregoing that once the scrubber bottle isfilled with water, the operation of the apparatus is entirely automatic.The rate of water evaporation automatically adjusts to changingconditions of atmospheric humidity.

The apparatus as shown in FIGURES l and 2 has no moving parts (exceptfor check valve 27), and is virtually maintenance-free. It is onlynecessary for the user to occasionally replenish the water in thescrubber bottle, and to empty and refill the scrubber bottle with waterwhen the layer of removed particulate matter reaches a thickness of oneto two inches on the water surface.

As stated previously, one of the objects of the present method andapparatus is the reduction in concentration of unburned hydrocarbons bysimultaneously ventilating the engine crankcase and humidifying thefuel-air mixture. The following table illustrates the reduction inhydrocarbon concentration obtainable with the present method andapparatus. The data in the table were obtained using a 1957 Chryslerautomobile engine having an indicated mileage of 108,350 miles. Theengine was driven through a 7-mode test cycle on a Clayton dynamometer.The exhaust gas was collected in an evacuated tank and analyzed forunburned hydrocarbons with a Beckman non-dispersive infraredspectrophotometer. Carbon dioxide, oxygen, and carbon monoxide weredetermined with a Fisher gas analyzer.

It can be seen from the foregoing table that installation of the presentapparatus on the test engine reduced the concentration of unburnedhydrocarbons in the exhaust gas by 41%. In addition, the concentrationof carbon monoxide in the exhaust gas Was reduced by 67%.

What is claimed is:

1. Apparatus for reducing the concentration of unburned hydrocarbons inautomobile exhaust gases comprising a container sealed at its upper endby a removable cap, an intake conduit communicated adjacent one end withthe lower inten'or end region of said container and adapted at the otherend for communicable connection to the crankcase interior of an internalcombustion engine, an exit conduit communicated at one end with theupper interior end region of said container and adapted at the other endfor communicable connection to the intake manifold of said engine, and anormally closed check valve mounted in said cap in communication withthe interior of said container.

2. The combination of an intern-a1 combustion engine including intakeand exhaust manifolds and a crankcase sealed from the atmosphere, atscrubber bottle partially filled with water and having a removable cap,an intake conduit extending into said bottle and communicating with theinterior thereof at a location beneath the level of said water, saidintake conduit communicably connected to the interior of said crank caseand being looped closely about said exhaust manifold whereby the heatthereof is imparted to said conduit, and an exit conduit extending intosaid bottle and communicating with the interior thereof at a locationabove the level of said water, said exit conduit communicably connectedto said intake manifold.

3. The combination of claim 2, further defined by a normally closedcheck valve mounted in said cap in communication with the interior ofsaid bottle and arranged to open when the pressure in the bottleinterior exceeds atmospheric pressure.

References Cited by the Examiner UNITED STATES PATENTS 2,166,720 7/1939Gorleski 123-119 X 2,184,141 12/1939 Dodge 123-119 X 2,185,320 1/1940Spearman 123119 2,646,784 7/1953 McKeeVer 123--1 19 X KARL J. ALBRECHT,Primary Examiner.

1. APPARATUS FOR REDUCING THE CONCENTRATION OF UNBURNED HYDROCARBONS INAUTOMOBILE EXHAUST GASES COMPRISING A CONTAINER SEALED AT ITS UPPER ENDBY A REMOVABLE CAP, AN INTAKE CONDUIT COMMUNICATED ADJACENT ONE END WITHTHE LOWER INTERIOR END REGION OF SAID CONTAINER AND ADAPTED AT THE OTHEREND FOR COMMUNUNICABLE CONNECTION TO THE CRANKCASE INTERIOR OF ANINTERNAL COMBUSTION ENGINE, AN EXIT CONDUIT COMMUNICATED AT ONE END WITHTHE UPPER INTERIOR END REGION OF SAID CONTAINER AND ADAPTED AT THE OTHEREND FOR COMMUNICABLE CONNECTION TO THE INTAKE MANIFOLD OF SAID ENGINE,AND A NORMALLY CLOSED CHECK VALVE MOUNTED IN SAID CAP IN COMMUNICATIONWITH THE INTERIOR OF SAID CONTAINER.